Shielding Studies using MARS Monte Carlo code

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Shielding Studies usingMARS Monte Carlo code
Jan. 6, 2005, WORKSHOP Machine-Detector Interface
at ILC, SLAC

• Noriaki Nakao (SLAC)

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Shielding Calculations by MARS code

• J-PARC
• 3GeV Proton Synchrotron
• (2001)
• SLAC LCLS
• 14.1GeV electron dump line
• (2004)

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J-PARC 3GeV Proton Synchrotron

• MARS14 (2001)
• Distributed beam loss
• using STRUCT (multi-turn tracking code)
• Beam line structure
• using MAD-MARS beam line builder
• Deep penetration calculation
• using 3-dimensional multi layer technique
• Prompt Residual dose rate estimation
• ? Shield thickness adjustment

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MARScalculationgeometry
J-PARC 3GeV Synchrotron
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Tunnel Cross Section at Injection and Collimator
Region
Vertical
Horizontal
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Beam loss distribution (Injection-collimator
region)
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Beam loss at injection septum
Horizontal
Injection septum
vertical
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Arc region geometry
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Magnetic fields
Bending Dipole
Focusing or DefocusingQuadrupole
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Flux estimation cells for MARS14 calculation
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3 dimensional multi layer calculationfor deep
penetration
1st layer Beam line module Tunnel inside shield
Leakage particles of previous layer are used as
source In 10 times multiplied Store
information of the particles leaked from geometry
boundary (x,y,z,dx,dy,dz,E,W)
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3 dimensional multi layer calculationfor deep
penetration
1st layer Beam line module Tunnel inside
shield 2nd layer Tunnel outside shield
Leakage particles of previous layer are used as
source of 10 times multiplied (splitting
method) Store information of the particles
leaked from geometry boundary (x,y,z,dx,dy,dz,E,W)
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3 dimensional multi layer calculationfor deep
penetration
1st layer Beam line module Tunnel inside
shield 2nd layer Tunnel outside shield 3rd
layer Soil around tunnel
Leakage particles of previous layer are used as
source of 10 times multiplied (splitting
method) Store information of the particles
leaked from geometry boundary (x,y,z,dx,dy,dz,E,W)
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3 dimensional multi layer calculationfor deep
penetration
Ground level
1st layer Beam line module Tunnel inside
shield 2nd layer Tunnel outside shield 3rd
layer Soil around tunnel Last layer Soil below
ground level
Leakage particles of previous layer are used as
source of 10 times multiplied (splitting
method) Store information of the particles
leaked from geometry boundary (x,y,z,dx,dy,dz,E,W)
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5mSv/h (500mrem/h)
Prompt dose rate mSv/h
0.25mSv/h (0.025mrem/h)
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SLAC LCLS - 14.1 GeV electron dump line

• MARS15(2004)
• Consider
• - Shielding, magnet, spoiler, collimator
• - Magnetic field
• Beam loss at (1) dump or (2) magnet
• Dose particle flux distribution (color 2D)

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Overview of MARS15 geometry for LCLS dump line
SOIL
Hutch
Muon shield
Muon shield
AIR
Horizontal view
30m
AIR
SOIL
Hutch
Muon shield
Muon shield
AIR
Concrete
Beam dump
Vertical view
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(1) 14.1 GeV-5kW electrons into the beam dump
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(No Transcript)
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Residual dose rate and muon flux around Beam
dump (14.1GeV 5kW electron beam)
Muon Flux
Residual dose rate
Residual dose rate mSv/h 30 day operation, 1
day cooling
Muon flux 1/cm2/sec
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Photon flux 1/cm2/sec
Electron flux 1/cm2/sec
Prompt dose mSv/h
Neutron flux 1/cm2/sec
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(2) 30W electron loss at bending magnet
SUS pipe at Bending magnet
1mrad angle
Horizontal
Vertical
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Beam loss at SUS pipe of the 1st-bending magnet)
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Prompt dose and muon flux (14.1GeV 30W beam loss
at 1st-bending magnet)
100 10 1 rem/h
100 10 1 0.1 mrem/h
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Summary

• Shielding studies were performed using MARS code
  for
• - J-PARC 3GeV Proton Synchrotron
• - SLAC LCLS Dump line
• Detailed structure of shielding, beam line
  modules, and magnetic fields were taken into
  account
• Spatial distributions were obtained for
• prompt residual dose rates, and
• particle flux (e, g, m, n etc.)